Treatment of motor fuel



Patented se t c, 193s.

PATENT orr cs TREATMENT or MOTOR FUEL Charles D. Lowry, Jr., Chicago. ill minor to Universal Oil Products Company, Chicago, lillt,

a corporation of Delaware No Drawing.

7 Claim.

This invention relates more particularly to the treatment of motor fuel either consisting entirelyoi or containing substantial percentages oi the lighter distillates produced in cracking operations 5 upon the heavier distillate and residual portion of petroleum oils though the treatment may also be utilized in connection with motor fuels produced from other raw hydrocarbon sources such as shale oil, coal, etc.

More specifically the invention is concerned with aparticular method of treatment which in- I sures the preservation of the more desirable properties of motor iuel while under storage conditions. This is accomplished by the use of novel materials whose-value in this connection has been hitherto unsuspected. Y

Until cracked motor fuels were produced in appreciable quantities to augment the failing supply of straight run gasolines, no special s so ficulties were encountered in the loss of desirable characteristics on storage as evidenced by the development oi undesirable color and high mm contentand loss in anti-knock value since the controlled distillation methods,'-contained little orno amount oi sumciently unsaturated hydro carbons which were susceptible to oxidation under'storage conditions. Cracked gasolines, however, have been shown to contain sumcient per- 0 centages oi dioleflns and similar. compounds to account for at least the major portion oi the ob served depreciation of gasolines under stora e conditions, these compounds forming peroxides initially by direct addition of oxygen to conjugated double bonds. These peroxides then instigate a series of chain reactions which result in formation of colored bodies, gums and resins and evidently account for the observed deterioration in anti-knock properties.

40 Chemical treatments aimed at the removal of the unstable hydrocarbons frequently entail the 1 loss of large percentages of distillates and are costly and cumbersome, so that recently a great deal of work has been done in the industry with the object of developing numerous types of soluble antioxidant materials which eliminate thenecessity for chemical treatment and inhibit the enact or oxygen upon' the gasolines by exerting for a time at least a preferential amnity therefor. The

' art involving the useot material which is readily available, inexpensive and effective not only as an inhibitor but also in other ways as will be disclosed in succeeding paragraphs. I

In one specific embodiment the invention com straight run gasolines, even it produced by poorly.

present invention is a contribution to the inhibitor Application Feb 5, 193%,. Serial No. 709,791

prises the use of unrefined corn oil as an inhibitor in unstable gasolines, particularly cracked gasolines. p I ve deteed by experiments, the results ofwhich will be given later that crude corn oil 5 produced by extraction or pressing of the corn germ contains considerable percentages of compounds which have an antioxidant action. This is evidenced prily by the fact that unrefined corn oil itself possesses great/er stability against rancidity than the refined product which has usually been treated with alkaliesto remove acidic and other types of organic compounds. Compounds which are evidently responsible l or the ob served antioxidant action are apparently the sterols which frequently comprise from lifts 3% of the crude oil. The chemical character 0! these 3 compounds merits some special attention.

The sterols have a complicated chemical struc ture and are usually considered as cyclic alcohols 2c of high molecular weight. They difier chemically-irom the aliphatic alcohols most essentially in that they are not converted into fatty acids having the some nber of carbon atoms by heating with soda 1:: 1: and similar alkaline reagents. Some of the representative members of this class oi compounds are shown below:

Cholesterol, phytosterol (sitosterol) sterol, brassiterol, coprosterol.

Of the members oi the above group cholesterol has is studied most extensively and is gener-. ally considered to be a complicated terpene com pound having the ionic. CZIHAGQ. Stmcturally it is reprted as iollows: (Lewlrowitschl a othermembers of the group have the same general formula but differ slightly in their structural arrangement. It is most likely that the particular sterol in corn oil is sitosterol, the presenceoi which has also been detected in oils fromwheat and other grains. Cholesterol has thus far not been detected in vegetable oils, in tact, its 45 presence is commonly considered as prima iacic evidence of the al origin or an oil or lat. In utilizing the process of the invention to treat and stabilize cracked gasolines, amounts 0! corn oil varying from i to approximately 5% are dis- 5o solved in the gasoline. The major portion of the oil which consists oi fatty acid esters performs a further useful iunction in that it assists in lubricating the topportion 0! the cylinders of the internal combustion engine in which the fuel is z.

oxygen bomb test and the change in gum content and antiknock value of the gasoline before and after the test.

As an example of results obtainable by using corn oil as an inhibitor in gasoline the following is cited though other examples are numerous and the invention is not limited by the particular data given. .4

A paraflinic cracked gasoline was found to have an induction period of only minutes in the oxygen- :bomb. The addition of 0.5% by volume of corn oil raised the induction period to 180 minutes and the addition of 2.5% of corn oil raised the 'induction period to 400 minutes, the latter' figure being considerably in excess of the 240 minute requirement which is generally conceded to indicate a practical 6 months storage stability. The scope of the-invention and the character of the' results' obtained by its use are evident from the foregoing specification and single' numerical example and it is to be understood that neither is 'to be construed in the light of imposing'undue limitations thereon;

claim as my invention:

1. A process for the treatment of hydrocarbon oil containing readily oxidizable unsaturates to prevent deterioration thereof in respect to gum and color formation, which comprises adding to the said hydrocarbon oil a small quantity of an unrefined corn oil.

2. A process for the treatment of cracked hy- 5 drocarbon oil to prevent deterioration thereof in respect to gum and color formation and deterioration of anti-knock properties, which comprises adding to the said cracked hydrocarbon oil a small quantity of an unrefined corn oil.

3. A process for the treatment of hydrocarbon 011 containing readily oxidizable unsaturates of substantially gasoline boiling range to prevent deterioration thereof in respect to gum and color formation and deterioration of anti-knock prop- 15 erties; which comprises adding to the said hydrocarbon oil a small quantity of an unrefined corn oil. 4. A process for the treatment of cracked gasoline to prevent deterioration thereof in respect :0

to'gumand color formation and deterioration of anti-knock properties, which comprises adding to the said cracked gasoline a small quantity of an unrefined corn oil 5. A method for preventing deterioration of :5 hydrocarbon material containing readily oxidizable unsaturates, which comprises adding to the hydrocarbon material a small quantity of unrefined corn oil.

6. A method for stabilizing motor fuel con- 30 taining unsaturated hydrocarbons produced by cracking. which comprises adding to the motor fuel a small amount of unrefined corn oil.

7. Motor fuel comprising cracked gasoline containing a relatively small amount of unrefined corn oil. v

CHARLES D. LOWRY JR. 

